Twin brothers in India

 Complete the “Inquiry Activity” on page 340

 Karyotype- A picture of chromosomes arranged in this way is known  Biologist use a Karyotype to find defects in the chromosome number

 Sex Chromosomes- c’somes that determine the sex (gender) of an organism  Humans females have:  have two copies of an X chromosome (XX)  Human males have:  Males have one X chromosome and one Y chromosome (XY)  Life cannot exist w/o the X c’some  Life can exist w/o the Y c’some

Human Female Karyotype (XX) Human Male Karyotype (XY)

 Autosomes- Any chromosomes that does not determine sex  Humans have 22 pairs or 44 autosomes and 1pair or 2 sex c’somes  A human male is 46, XY  A human female is 46, XX  There is a 50:50 chance of a person being male of female

 Pedigree-a diagram that shows the occurrence and appearance or phenotypes of a particular gene or organism and its ancestors from one generation to the next

 Pg. 343 Problem Solving complete

 Genes & the Environment- many human traits are controlled by many genes or polygenic  Height  Body shape  Skin color, etc

 5 ways your environment can determine how you features (how you look)

 Environment plays a role also  Temp  Diet  Geography  Smoke, alcohol abuse, drug abuse, etc.

 All humans and many other primates can be typed for the ABO blood group  There are four phenotypes: A, B, AB, and O  There are two antigens and two antibodies that are mostly responsible for the ABO types

 There are two types of inherited disorders in humans; recessive & dominant  Recessive Disorders  Most human disorders are recessive  Cystic Fibrosis is common in the U.S.  Excessive mucus secretion clogs the lungs Few black people have the disease (1/17,000) More white people have the disease (1/1,800)

 Dominant Disorders  Only copy of allele needs to present for the disordered to have the disease